1. Field of the Invention
The present invention relates to control circuits of liquid crystal display devices, liquid crystal display devices, and electronic devices provided with liquid crystal display devices.
2. Description of the Related Art
Liquid crystal display devices ranging from a large display device such as a television receiver to a small display device such as a mobile phone have been spreading. From now on, products with higher added values will be needed and are being developed. In addition, there has been a growing interest in global environment, and the development of liquid crystal display devices consuming less power has thus attracted attention.
Non-Patent Document 1 discloses a structure of a liquid crystal display device where refresh rates differ between the case of moving image display and the case of still image display in order to achieve low power consumption of the liquid crystal display device.
In addition, in the liquid crystal display device, liquid crystal molecules are sandwiched between a pixel electrode and a counter electrode, and the alignment of the liquid crystal molecules is controlled by a voltage which is applied between the pixel electrode and the counter electrode. The voltage of the pixel electrode is set to a desired level by controlling switching of a thin film transistor provided in each pixel. The counter electrode is provided on a counter substrate provided with liquid crystal molecules which are sandwiched between the counter substrate and a substrate provided with the pixel electrode. The counter electrode is not provided for each pixel but provided over the entire surface; therefore, the voltage of the counter electrode is controlled to have a predetermined level by an operational amplifier in a power supply circuit.
A circuit configuration of the operational amplifier used in the liquid crystal display device is disclosed in Patent Document 1 (e.g., see FIG. 6).